Product dispensing apparatus

ABSTRACT

A product dispensing apparatus for filling a container with product material has an enclosure for holding a supply of product material, a discharge outlet in the enclosure, and a gate device mounted adjacent the discharge outlet for controlling the flow of material through the outlet. The gate device is provided with a plate slidable across the discharge outlet between a fully closed position wherein the plate completely covers the discharge outlet and a maximum open position wherein the plate is generally clear of the discharge outlet and one or more partially open positions located between the maximum open and fully closed positions. The gate device is further provided with an actuator having a driven member connected to the plate for moving the plate among the closed, maximum open, and partially open positions, and stopping means adjacent the actuator for stopping the plate at the partially open positions.

FIELD OF THE INVENTION

This invention relates to product dispensing equipment for dispensingproduct material into containers.

BACKGROUND OF THE INVENTION

Product dispensing systems can be used for dispensing a product, such assugar or flour, into containers for sale or transport. It isadvantageous that these dispensing systems fill the containers quicklyso that production time (and associated costs) are kept to a minimum. Itis also desirable that these dispensing systems fill the containers withan accurate amount of product so that a consumer is getting at least theamount of product stated on the container without overfilling thecontainer. Any overfill would of course amount to giving product awaywithout receiving any payment for such product.

Canadian Patent Application 2,276,757 (Salaoras) discloses a productdelivery system having a sliding gate. The sliding gate is movablebetween a plurality of positions corresponding to different outletopenings through which the product is dispensed. By controlling the sizeof the outlet opening, the product can be dispensed at a rapid rate inthe initial filling process, and at progressively slower rates whenapproaching the target product delivery amount.

The sliding gate in the '757 patent is controlled by a plurality ofpneumatic cylinders. As a result of the multiple air cylinders, arelatively complicated network of piping is required to connect each aircylinder to a pressurized air supply. Furthermore, using a plurality ofcylinders to provide multiple plate positions for the sliding gaterequires elaborate mountings for interconnecting the cylinders.Accordingly, the delivery device is rather complex and costly tomanufacture, is susceptible to a higher incidence of failure, and isrelatively difficult to service.

SUMMARY OF THE INVENTION

It is an object of the present invention to improve on the prior art. Itis another object of the invention to provide a product dispensingdevice having a sliding gate for controlling the flow of product fromthe device. It is another object to provide a dispensing apparatushaving a gate device and configured to move the gate device among open,closed, and pre-selected intermediate positions quickly and accurately.It is another object to provide a dispensing apparatus having a gatedevice with easily adjustable pre-selected intermediate positions. It isanother object of the present invention to provide a dispensingapparatus with a gate device that operates reliably and is easy tomaintain. These and other objects are provided by features described inthe claims. The following summary provides an introduction to theinvention which may reside in a combination or sub-combination offeatures provided in this summary or in other parts of this document.

According to one aspect of the present invention, a product dispensingapparatus for filling a container with product material is provided. Theapparatus has an enclosure for holding a supply of product material, adischarge outlet in the enclosure, and a gate device mounted adjacentthe discharge outlet for controlling the flow of material through theoutlet.

The gate device is provided with a plate slidable across the dischargeoutlet between a fully closed position wherein the plate completelycovers the discharge outlet and a maximum open position wherein theplate is generally clear of the discharge outlet and one or morepartially open positions located between the maximum open and fullyclosed positions.

The gate device is further provided with an actuator having a drivenmember connected to the plate for moving the plate among the closed,maximum open, and partially open positions, and stopping means adjacentthe actuator for stopping the plate at the partially open positions.

The stopping means can include a brake having a locking element forreleasably engaging at least one of the driven member of the actuatorand the plate.

The dispensing apparatus can include a control system in communicationwith the brake, and brake control means for activating and deactivatingthe brake. The brake can be controlled pneumatically, using air pressureis to control the activation and deactivation of the brake.

The control system can include sensors adjacent at least one of theplate and the actuator, the sensors adapted to detect the position ofthe plate corresponding to each the partially open positions and to senda corresponding signal to the control system.

The dispensing apparatus can have a fill sensor for detecting the amountof product material dispensed into the container. The fill sensor can bea transducer in electrical communication with the control system.

The dispensing apparatus can include a container holding device fromwhich an upper end of the container is suspended, and a suspensionframework to which the container holding device is secured. Thecontainer holding device can be movable in a vertical plane relative tothe suspension framework. The transducer can be mounted between aportion of the container holding device and the suspension framework sothat a force is applied across the transducer in proportion to theweight of the container.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and to show moreclearly how it may be carried into effect, reference will now be made byway of example to the accompanying drawings that show embodiments of thepresent invention, and in which:

FIG. 1 is a front view of a dispensing apparatus according to thepresent invention;

FIG. 2 is a portion of the apparatus of FIG. 1 showing a gate device andadjacent elements in greater detail;

FIGS. 3 a-3 e show the gate device of FIG. 2 with a plate in differentpositions;

FIG. 4 is a top view of the gate device of FIG. 2;

FIG. 5 is a section view of the gate device of FIG. 4 taken along thelines 5-5;

FIG. 6 is a section view of the gate device of FIG. 4 taken along thelines 6-6;

FIG. 7 is a perspective view of a slide frame of the gate device of FIG.2;

FIG. 8 is a cross-sectional view of a stopping device of the apparatusof FIG. 1;

FIG. 9 is a cut-away view of a control system of the apparatus of FIG.1;

FIG. 10 is an enlarged view of a portion of the apparatus of FIG. 1showing a container holder device in greater detail;

FIG. 11 is a side view showing details of an alternate configuration formounting and sensing the weight of a container to be filled by theapparatus of FIG. 1; and

FIG. 12 is a rear view of a portion of the apparatus of FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION

A product dispensing apparatus according to the present invention isshown generally at 100 in FIG. 1. The product dispensing apparatus 100has an enclosure 102 for holding product material 104 to be dispensed, adischarge outlet 106 in the enclosure 102, and a gate device 108 mountedadjacent the discharge outlet 106 for controlling the flow of theproduct material 104 from the enclosure 102 through the outlet 106.

In the illustrated embodiment, the enclosure 102 is in the form of ahopper 110 having sidewalls 112. The hopper 110 has an upper inletopening 114 for receiving a supply of the product material 104, and alower end 116 from which the discharge outlet 106 extends.

The hopper 110 is supported above a floor by a support structure 118 sothat a container 119 into which the product material is to be dispensedcan be positioned below the discharge outlet 106 of the hopper 110. Moreparticularly, in the embodiment illustrated, a container holding device120 is provided below the outlet 106 and supported in place by thesupport structure 118. The container 119, which in the illustratedembodiment is in the form of a bag, can be suspended from the containerholding device 120. Further details of the container holding device 120are provided hereinafter.

Referring now to FIG. 2, the gate device 108 of the apparatus 100 ismounted below the discharge outlet 106, and above the container 119. Thegate device 108 has a plate 126 that is slidable across the dischargeoutlet 106. In the illustrated embodiment, the plate is linearlyslidable along a slide axis 127. The plate 126 can slide among aplurality of plate positions 128 to vary the amount by which the plate126 obstructs the discharge outlet 106. Increasing or decreasing theamount by which the plate 126 obstructs the outlet 106 causes acorresponding decrease or increase in the effective size of the openingthrough which product material 104 can escape the hopper 110.

Referring now to FIGS. 3 a-3 e, the plurality of plate positions 128 ofthe plate 126 includes a fully closed position 128 a (FIG. 3 a) in whichthe plate 126 completely obstructs the discharge outlet 106, a maximumopen position 128 b (FIG. 3 b) in which the plate 126 is generally clearof the discharge outlet 106, and one or more partially open positions128 c in which the plate 126 is between the fully closed 128 a andmaximum open 128 b positions. In the embodiment illustrated, the plate126 has three partially open positions 128 c, namely 128 c-1 (FIG. 3 c),128 c-2 (FIG. 3 d), and 128 c-3 (FIG. 3 e), corresponding toapproximately 60% open, 30% open, and 5% open conditions of the outlet106 (relative to cross-sectional area of the maximum open position 128b). The three partially open positions 128 c are set using gate positionsensors 129, as will be further described hereinafter.

Referring again to FIG. 2, to slidably support the plate 126 adjacentthe outlet 106, the illustrated embodiment of the gate device 108 isprovided with a gate housing 130. As best seen in FIGS. 4-6, the gatehousing 130 has two parallel, spaced apart retaining panels 132 eachhaving an aperture 134 at one end and support legs 136 extending awayfrom the aperture 134.

A slide frame 140 (see also FIG. 7) is sandwiched between the two panels132 such that the frame 140 is in alignment with the apertures 134. Moreparticularly, the slide frame 140 has opposing longitudinal side members142 oriented parallel to the slide axis 127, and opposing front and reartransverse members 144, 146 extending between the side members 142. Themembers 142, 144, 146 of the frame 140 present interior surfaces 148that are aligned with the perimeter of the apertures 134 in theretaining panels 132. Accordingly, the frame 140 and the apertures 134cooperate to form a generally continuous channel 135 through the gatehousing 130.

Longitudinal grooves 150 are provided along the interior surfaces 148 ofthe longitudinal side members 142 of the slide frame 140. The grooves150 are sized to receive the side edges of the plate 126 in sliding fit.The rear transverse member 146 has a slot 152 through which the plate126 can slide. The slot 152 extends transversely between thelongitudinal grooves 150 of the opposing side members 142, and theheight of slot 152 is sized to be slightly greater than thickness of theplate 126. The front transverse member 144 can have a transverse groove154 along its interior surface 148, to receive the front edge of theplate 126. Engagement of the front (or leading) edge of the plate 126 inthe transverse groove 154 can improve the obstructing action of theoutlet 106 by the plate 126 when the plate 126 is in the fully closedposition 128 a.

The gate housing 130 is secured to the lower end 116 of the hopper 110such that the discharge outlet 106 of the hopper and the channel 135 ofthe housing 130 are substantially aligned. Shrouding or funneling panels(not shown) can be installed between the outlet 106 and the gate housing130 to ensure that any product material 104 leaving the outlet 106 isdirected into the channel 135 of the housing 130. By sliding the plate126 within the slide frame 140, any desired degree of obstruction of thechannel 135, and hence of the outlet 106, can be provided.

The housing 130 (and hence the plate 126) can be oriented at an inclinefrom the horizontal to inhibit jamming of the plate 126 when the plate126 moves in a direction from the maximum open position 128 b towardsthe fully closed position 128 a (FIG. 2). In the embodiment illustrated,the plate 126 is inclined so that leading edge is at a lower elevationthan the trailing edge. The amount of incline is about 20-30 degreesfrom the horizontal.

Referring still to FIGS. 4-6, the gate device 108 of the apparatus 100is further provided with an actuator 160 having a driven member 162connected to the plate 126, for moving the plate 126 among the variousplate positions 128. The actuator 160 can be in the form of, forexample, but not limited to, a pneumatic cylinder (rod or rodlesstypes), a hydraulic cylinder, or a motor driven actuator.

In the embodiment illustrated, the actuator 160 comprises a pneumaticcylinder 161 having an extensible/retractable cylinder rod 163 as thedriven member 162. A coupling bracket 164 can be provided between theplate 126 and the rod 163, for connecting the plate 126 and the rod 163together. The cylinder 161 has a stationary housing portion 165 that canbe secured to the gate housing 130. A mounting bar 138 can be providedbetween the ends of the legs 136 for supporting the housing portion 165of the cylinder 161.

Advance and return air lines 166 and 168 extend from rear and front ends170, 172 of the cylinder 161, respectively. Supplying pressurized air tothe advance air line 166 moves the plate 126 towards the fully closedposition 128 a, and supplying pressurized air to the return air line 168moves the plate 126 towards the maximum open position 128 b.

To stop the plate 126 at any one of the various plate positions 128, thegate device 108 is provided with stopping means 176 for releasablyengaging at least one of the driven member 162 of the actuator 160 andthe plate 126. In the embodiment illustrated, the stopping means 176 ismounted adjacent the front end 172 of the actuator 160 and releasablyengages the driven member 162 of the actuator 160.

Referring now to FIG. 8, in the illustrated embodiment the stoppingmeans 176 comprises a pneumatic brake 177 mounted adjacent the cylinder161. The brake 177 has an axial bore 178 through which the rod 163 ofthe cylinder 161 passes, and a locking element 180 movable betweenengaged and released positions 182, 184, respectively. When in theengaged position 182, the locking element 180 engages the cylinder rod163 so that axial movement of the rod 163 is inhibited. When in thereleased position 184, the locking element 180 is clear of the cylinderrod 163 so that the rod 163 can slide smoothly through the bore 178.

In the illustrated embodiment, the locking element 180 comprises a pairof brake shoes 181 a, 181 b disposed on opposite sides of the rod 163.The locking element 180 is mechanically biased towards the engagedposition 182 by a compression spring 185. The locking element 180 can bemoved to the released position 184 by providing pressurized air to abrake air line 186. An auxiliary locking air line can be provided to thebrake 177 to work with the spring 185 in urging the locking element 180to the engaged position 182.

The present invention comprehends the use of stopping means 166 otherthan a pneumatic brake 177. For example, if a hydraulic actuator isused, back pressure can be used in the actuator to stop the motion ofthe driven member. If a motor controlled actuator is used, the stoppingmeans 176 can be in the form of a mechanical brake, or alternatively,electrical current can be used to provide a stopping and/or holdingtorque on the motor.

Referring now to FIG. 9, to control the movement of the plate 126 by theactuator 160, the apparatus 100 may be provided with a control system190. The control system 190 can include a controller 192, which can be,for example, but not limited to, a Programmable Logic Controller (PLC).

The control system 190 in the illustrated embodiment is provided withactuator control means 194 and brake control means 196 in communicationwith a PLC 192. The cylinder control means 194 includes an advance and areturn valve 200, 202, respectively, fitted in line with the advance andreturn air lines 166, 168, respectively. The valves 200 and 202 areprovided with solenoids 204 for moving the valves between open andclosed positions. Similarly, the brake control means 196 comprises abrake valve 208 fitted in line with the brake air line 186. The brakevalve 208 is also equipped with a solenoid 204 for actuation of thevalve. The solenoids 204 are in electrical communication with the PLC192, so that the PLC 192 can send electrical signals to the solenoids204 and so advance and return the cylinder rod 163, and move the brakebetween the engaged and released positions 182, 184.

The control system 190 also includes position sensors 210 adjacent atleast one of the plate 126 or the actuator 160 for detecting the axialposition of the plate 126. More specifically, position sensors 210 canbe placed adjacent the path of travel of the plate 126 and/or the drivenmember 162 of the actuator 160, at locations along the path of travelcorresponding to the various plate positions 128. The position sensorscan be in the form of, for example, but not limited to, proximitysensors or limit switches. Digital encoders can also be used to provideposition gearing feedback signals to the OLC 192.

In the illustrated embodiment, the sensors 210 are in are in the form ofmagnetic reed switches, and the rod 163 of the actuator 160 is providedwith a magnet 212 that trips the switches 210 when passing. The sensors210 c-1, 210 c-2, and 210 c-3 are fastened to the housing 165 of thecylinder 161 at positions corresponding to the position of the magnet212 when the plate 126 is in the partially open positions 128 c-1, 128c-2, and 128 c-3, respectively.

To move the plate 126 between, for example, the partially open positions128 c-1 and 128 c-2, the PLC 192 energizes the solenoid 204 on the brakevalve 208 to release the brake. Then solenoid 204 on the advance valve200 is energized, so that the rod 163 of the cylinder 161 advances. Whenthe magnet 212 passes and trips the position sensor 210 c-2, the PLCimmediately de-energizes the solenoid 204 on the brake valve 208 so thatthe brake moves to the engaged position 182. As well, the advance valve200 can be shuttled so that air supply to air line 166 is shut off. Therod 163, and hence the plate 126, is thereby stopped at the partiallyopen position 128 c-2.

It is to be appreciated that the location of the position sensors 210 calong the travel path of the rod 161 and or plate 126 effectivelyestablish the axial location of plate corresponding to each of thepartially open positions 128 c. These locations can be adjusted tooptimize the dispensing cycle for various product materials 104 that maybe dispensed.

Using the sensors 210 at the partially open positions 128 c of the plate126 has been explicitly referred to above. A person skilled in the artwill appreciate that positions sensors 210 may not be required fordetecting the fully closed 128 a or maximum open 128 b positions of theplate 126 because it is usually possible to set up the cylinder 161 suchthat the rod 163 has a maximum stroke length equal to the distancebetween the two extreme plate positions 128 a and 128 b. In other words,at those positions, the position of the rod 163 (and hence the plate126) can be defined by allowing the cylinder 161 to bottom out or tocontact a fixed abutment (positive stop). Nevertheless, it may beadvantageous to provide sensors 210 a and 210 b at the fully closed 128a and maximum open 128 b positions for a number of reasons. Thesereasons can include, for example, a reduction in wear and tear on thecylinder 161, and to provide additional flexibility in controlling thedispense cycle by adjusting these positions 128 a and 128 b(particularly the maximum open position 128 b).

The control system 190 of the apparatus 100 may further be provided witha fill sensor 218 for detecting the amount of product material 104dispensed into the container 119. The fill sensor 218 can be in the formof, for example, but not limited to, a weight sensor such as a loadcell, or a volume sensor such as distance or photoelectric sensors. Inthe illustrated embodiment, the fill sensor 218 comprises a transducer(or load cell) 219 for measuring the weight of the container 119containing product material 104.

As best seen in FIG. 10, the transducer 219 is mounted such that theweight of the container 119 (and its contents) is proportional to acompressive force 220 applied across the transducer 219. This cangenerally be accomplished by providing a suspension framework 221 fromwhich the container holding device 120 (with an attached container 119)is suspended. The container holding device 120 is movably secured to thesuspension framework at least in a vertical plane, and the transducer219 can be positioned between the movable holding device 120 and thesuspension framework 121. At least a portion of the weight of thecontainer holding device 120 (and attached container 119) can bearagainst the transducer 219.

As best seen in FIG. 10, in one embodiment, the suspension framework 221comprises a pair of vertical legs 222 extending from the frame 118 onopposed sides of the discharge outlet 106. A generally horizontal shelfportion 224 extends inwardly from one leg 222. A horizontal hanger arm238 extends inwardly from the opposed leg 222.

The container holding device 120 has upper and lower horizontal members226 and 228, respectively, and uprights 230 extending between thehorizontal members 226, 228, and on opposite sides of the dischargeoutlet 106. In the illustrated embodiment, the container holding device120 is further provided with a bag clamp assembly 232 secured to thelower horizontal member 228, such that the container 119 can besuspended from the holding device 120.

The container holding device 120 is pivotably secured to the suspensionframework 221 by means of a pivot bolt 234 passing horizontally throughone of the uprights 230 and the hanger arm 238. The upper horizontalmember 226 of the holding device 120 has an extension arm 240 that ispositioned vertically above the shelf portion 224 of the mountingbracket 222. The transducer 219 is mounted between the shelf portion 224and the arm 240. Since the holding device 120 can pivot about the pivotbolt 234, an increase in weight of the container 119 holding productmaterial 104 is reflected in an increased compressive force 220 exertedby the arm 240 on the transducer 219. Accordingly, as the container 119is filled with product material 104, the downward force 220 exerted bythe arm 240 on the transducer 219 increases. The transducer 219 sends anelectrical signal to the PLC 192 which varies in accordance with themagnitude of the downward force 220.

The mounting location of the transducer 219 according to this embodimentis above the container 119, which reduces the possibility of thetransducer 219 becoming contaminated or damaged by spillage of theproduct material 104. Furthermore, the motion of the arm 240 whenexerting the force 220 on the transducer 219 is limited to a singleaxis, namely, a rotational axis about the pivot bolt 234. This canreduce the amount of vibration or other undesirable forces transmittedto the load cell, so that more accurate weight measurement is possible.

Referring now to FIGS. 11 and 12, an alternative transducer mountingconfiguration includes a suspension framework 321 and a containerholding device 320. The suspension framework 321 has a generallyhorizontal shelf portion 324 extending between vertical webs 325. Thevertical webs 325 are secured to extend downward from the gate housing130 adjacent the discharge outlet 106. The transducer 219 is mounted onthe shelf portion 324, between the webs 325.

The container holding device 320 has a bracket arm 330 and a bag clampassembly 332. The bracket arm 330 has an upper horizontal hanger bar 334with vertical plates 336 extending downward and outward from the hangerbar 334. The hanger bar 334 extends generally parallel to the shelf 324,and is secured at the central portion to an upper surface of thetransducer. The vertical plates 336 extend outward to a positiongenerally underneath the discharge outlet 106. The bag clamp assembly332 is suspended from the vertical plates 336. This configurationprovides an essentially cantilevered mounting arrangement of thecontainer holding device 320 relative to the suspension framework 321,which in turn allows movement of the container holding device in agenerally vertical plane, relative to the suspension framework 321.Accordingly, the weight of the bag 119 secured to the bag clamp assembly332 is reflected in the magnitude of the force 220 exerted on thetransducer 219, which is sandwiched between the shelf 324 and hanger bar334.

In the embodiment illustrated, to secure the bag clamp assembly 332 tothe plates 336, the plates 336 are provided with generally parallelhorizontal slots 338 that are open to a forward edge 340 of the plates336. The bag clamp assembly 332 has a structural hoop 342 for lining thethroat of the bag 119, and a pair of pins 344 extending generallyhorizontally and outwardly from either side of the hoop 342. The pins344 are sized to be slidingly received in the slots 338 of the plates336. The pins 344 can be in the form of bolts with thumb tabs tofacilitate installation and removal of the bag clamp assembly 332 fromthe arm 330.

The mounting bracket 322 and the container holding device 320 provide atransducer mounting configuration wherein the transducer is mountedabove the container 119, rather than below the container 119. As well,the cantilevered arrangement of the arm 330 relative to the transducer219 provides freedom of movement of the results in the force 220 exertedon the transducer 219 to follow a generally single-axis vector, namely,a moment that results from the action and reaction forces acting atspaced apart locations along the body of the transducer 219. This canimprove the accuracy of the signal generated by the transducer 219 byisolating or filtering “noise” generated by vibration and othermechanical effects.

In use, the PLC 192 can continuously monitor the transducer 219 during afill cycle, to keep track of how full the container 119 is getting. Asthe weight of the container 119 increases, the plate 126 of the gatedevice 108 can be moved to successively less open (or more obstructed)positions 128.

Use of the transducer 219 to trigger changes in the position 128 of theplate 126 can be accomplished by, for example, but not limited to,establishing discrete pre-selected weight set-points, which are lessthan the target weight of a “filled” container 119. When the PLC 192acknowledges that a particular set-point has been reached, the positionof the plate 126 can be adjusted by the PLC as described previously.

In a particular method for dispensing product material 104 using theapparatus 100 of the present invention, three pre-selected weightset-points are established. The first set-point is set at a weightcorresponding to about 50% of the target (filled) weight. The second andthird set-points are set at about 75% and 90% of the target weight,respectively. The method provides a two-stage dispensing cycle, namely,a bulk dispensing stage and a dribble dispensing stage. The bulkdispensing stage fills the container 119 to about 90-95% of the targetweight in a minimum amount of time. The dribble dispensing stage fillsthe container 119 to 100% of the target weight.

Before initiating the bulk dispensing cycle, certain start conditionsmust be satisfied. These start conditions include securing an emptycontainer 119 to the container holding device 120. As well, the plate126 should be in the fully closed position 128 a. The transducer 119 canbe tared and calibrated, if required.

The bulk dispensing cycle can then be initiated, either manually orautomatically (using sensors to confirm that the start conditions havebeen satisfied). The plate 126 is moved from the fully closed position128 a to the maximum open position 128 b, by controlling the brake 177and cylinder 161, as described previously. Moving the plate 126 awayfrom the fully closed position 128 a allows product material 104 to flowfrom the hopper 110 into the container 119, which accordingly increasesthe force 220 on the transducer 219.

When the transducer 219 signals that the container 119 has reached thefirst set-point, the plate 126 is moved to the first partially openposition 128 c-1. This increases the obstruction of the discharge outlet106 by the plate 126, so that the product material 104 continues to bedispensed into the container 119, but at a reduced rate.

When the second weight-set point is reached, the PLC 192 moves the plate126 to the second partially open position 128 c-2 to further reduce thefill rate. These reductions in the fill rate reduce the chance ofoverfilling the container 119 while yet maintaining a relatively fastfill rate.

When the third set-point is reached, the container 119 is almost filledto final target and the bulk dispensing cycle ends. The plate 126 ismoved to the fully closed position 128 a.

Before starting the dribble dispensing cycle, the controller pauses fora stabilization delay to ensure a stable, accurate weight measurement isbeing read by the transducer 219. Lower than actual weight readings canresult from material 104 having passed through the outlet 106 and theplate 126, but not yet having settled in the container 119. Higher thanactual weight readings (or spikes) can result from the force of theimpact of the dispensing material 104 landing upon the dispensedmaterial 104 already in the container 119. The stabilization delayallows the product material 104 to settle in the container 119 so thatthe chance of registering inaccurate weight readings is minimized.

After the stabilization delay, the container 119 will still be slightlyless than full. The dribble dispensing stage then begins by shuttlingthe plate 126 from the fully closed position 128 a to the thirdpartially open position 128 c-3, and then immediately back to the fullyclosed position 128 a. This dispenses a single shot (or batch) ofproduct material 104 into the container 119. The PLC 192 again pausesfor the stabilization delay and then compares the weight sensed by thetransducer 219 to the target weight. If the measured weight of thecontainer 119 is below the target weight, the dribble routine isrepeated. If the target weight has been reached or exceeded, thedispensing cycle is complete.

This method has been found to produce very favourable performance infilling containers 119. The method has been found to be much faster thanexisting filling methods, and fills the containers 119 to a moreaccurate level. In addition, the apparatus 100 has fewer moving partsthan previous dispensing apparatus, and is easier and less costly tomaintain. As well, the apparatus is highly flexible in that thedispensing cycles can conveniently be adjusted to optimize the cycletime and accuracy in response to the type of product material 104 beingdispensed and/or the type of container 119 being filled. For example,the quantity and magnitude of the weight set-points can adjusted bysimply altering the PLC program. As well, the quantity and axialposition of the sensors 210 along the travel path of the cylinder 160and/or plate 126 can be easily altered.

While preferred embodiments of the invention have been described hereinin detail, it is to be understood that this description is by way ofexample only, and is not intended to be limiting. The full scope of theinvention is to be determined from reference to the appended claims.

1. A product delivery apparatus for filling a container with productmaterial, the apparatus comprising: a) an enclosure for holding a supplyof product material; b) a discharge outlet in the enclosure; and c) agate device mounted adjacent the discharge outlet for controlling theflow of material through the outlet, the gate device comprising: i) aplate slidable across the discharge outlet between a fully closedposition wherein the plate completely covers the discharge outlet and amaximum open position wherein the plate is generally clear of thedischarge outlet and one or more partially open positions locatedbetween the maximum open and fully closed positions; ii) an actuatorhaving a driven member connected to the plate for moving the plate amongthe closed, maximum open, and partially open positions; and iii)stopping means adjacent the actuator for stopping the plate at least atthe partially open positions.
 2. The apparatus of claim 1 wherein thestopping means comprises a brake having a locking element for releasablyengaging at least one of the driven member of the actuator and theplate.
 3. The apparatus of claim 2 further comprising a control systemin communication with the brake and having brake control means foractivating and deactivating the brake.
 4. The apparatus of claim 3wherein air pressure is used to control the activation and deactivationof the brake.
 5. The apparatus of claim 3 wherein the control systemfurther comprises sensors adjacent at least one of the plate and theactuator, the sensors adapted to detect the position of the platecorresponding to each the partially open positions and to send acorresponding signal to the control system.
 6. The apparatus of claim 3further comprising a fill sensor for detecting the amount of productmaterial dispensed into the container.
 7. The apparatus of claim 6wherein the fill sensor comprises a transducer in electricalcommunication with the control system.
 8. The apparatus of claim 7further comprising a container holding device from which an upper end ofthe container is suspended, and a suspension framework to which thecontainer holding device is secured.
 9. The apparatus of claim 8 whereinthe container holding device is movable in a vertical plane relative tothe suspension framework.
 10. The apparatus of claim 9 wherein thetransducer is mounted between a portion of the container holding deviceand the suspension framework so that a force is applied across thetransducer in proportion to the weight of the container.